1. Field of the Invention
The present invention relates to an outboard motor mounted on the hull of a boat for generating power to propel the boat.
2. Description of the Related Art
Many outboard motors are equipped with a PTT (Power Trim and Tilt) device for driving an actuator to increase and decrease a vertical tilt angle of an outboard motor body with respect to a hull. A PTT switch unit for a user to operate the PTT device is provided, for example, on such places as a tiller handle, a remote controller, and an operation panel ahead of a cockpit of the boat (see Patent Document 1).
The outboard motor generally changes the rotational speed of an engine in response to rotation of a throttle grip provided, for example, at a tip end portion of the tiller handle, and thereby changes the speed of the boat. However, some outboard motors have a function of trolling operation, in which the speed of the boat is changed by limiting the speed of the boat to a predetermined low-speed range for performing trolling operation (low speed operation) and changing the rotational speed of the engine in this limited speed range not in response to the rotation of the throttle grip but in response to pressing of a pushbutton switch for trolling operation speed adjustment. The switch unit for trolling operation speed adjustment is provided, for example, on such places as a tiller handle, a remote controller, and an operation panel ahead of a cockpit of the boat (see Patent Document 2).
In the case of providing the outboard motor with the trolling operation function in addition to the function of tilting the outboard motor body with use of the PTT device, it is necessary to provide not only the PTT switch unit but also the switch unit for trolling operation speed adjustment on the places such as a tiller handle, a remote controller, and an operation panel. Accordingly, the number of switch units provided on the outboard motor or the boat increases, which increases manufacturing costs of the outboard motor or the boat.
Moreover, the tiller handle is a bar-like member extending from the body of the outboard motor body and does not have a large flat surface. Consequently, it is unfortunately not easy to place the switch unit for trolling operation speed adjustment as well as the PTT switch unit on the tiller handle while securing the operability of these units.
The PTT switch unit also has an UP switch for increasing the tilt angle of the outboard motor body and a DOWN switch for decreasing the tilt angle of the outboard motor body. The switch unit for trolling operation speed adjustment has an UP switch for increasing the rotational speed of the engine as long as the speed of the boat is kept in the aforementioned limited speed range and a DOWN switch for decreasing the rotational speed of the engine as long as the speed of the boat is kept in the aforementioned limited speed range. Thus, the PTT switch unit and the switch unit for trolling operation speed adjustment are in common with each other in the point that both the units have the UP switch and the DOWN switch. As a result, operation of these two switch units may erroneously be conducted because the user may operate the switch unit for trolling operation speed adjustment instead of the PTT switch unit by mistake, or user may accidentally operate the PTT switch unit instead of the switch unit for trolling operation speed adjustment.
It is desirable to mount the switch unit for trolling operation speed adjustment in the vicinity of a throttle grip of a tiller handle or in the vicinity of a shift lever of a remote controller. More specifically, if the switch unit for trolling operation speed adjustment can be provided in the vicinity of the throttle grip of the tiller handle or in the vicinity of the shift lever of the remote controller, the user can press each switch button in the switch unit for trolling operation speed adjustment while gripping the throttle grip of the tiller handle or the shift lever of the remote controller. Consequently, it becomes unnecessary for the user to take his/her hand from the throttle grip, the handle, or the shift lever of the remote controller in order to press each switch button in the switch unit for trolling operation speed adjustment during driving of the boat. It becomes also unnecessary for the user to widely move his/her gaze for pressing each switch button in the switch unit. This makes it possible to provide easy operability of the boat to the user and to also enhance the safety of driving.
[Patent Document 1] Japanese Laid-open Patent Publication No. 10-250688
[Patent Document 2] Japanese Laid-open Patent Publication No. 2005-319881